Hi,

Im trying to connect PLC (Carel pCO Compact) to ABB ANR96 via Modbus RTU. So far I have no real results. My knowledge about Modbus is quite constricted, so there probably is some foolish mistake in the way I'm doing things.

I have managed to use modbus with the same PLC and another devices, but not with ANR96. Also haven't manged to make it work with ABB DMTME.

I have tried to test the communication and addresses (which are given in manual) with ANR96 and PC using RS232 cable and Modbus Poll -program. The connection seems to work, but i'm getting weird values, which fit nowhere near the real ones. Also the address numbers aren't the same that are shown in the manual.

e.g. ANR96 manual shows Table Of Anr Registers, in which it shows that Integer Register HEX $1000 should contain value of 3-PHASE SYSTEM VOLTAGE.

So if I convert that to DEC its 4096. If i use Modbus Poll to scan addresses starting from 4096 the first value I get is in address 4098 and is constant 6. Address 4099 contains some weird value which fluctuates between 3000-6000.

As of Modbus Poll settings im using:
Protocol: Modbus RTU
Data bits: 8
Baud Rate: 9600 bps
Parity: None
Stop bit: 1
Slave ID:1

and in ANR96 I have set the same values (Id Address 1).

Next thing Im trying is to get ABB RS232/RS485 serial converter and try with that. But somehow im not confident it helps as ANR96 does have built in RS233 port.

So hopefully someone can point me what am I doing wrong?

Thanks for reading.

 

Hi,

you are getting correct values... 1000h = 4096 dec so when you read value of 1000h its returning 2 sets of 16 bit numbers so you receive data to 4096 + 4097 lower values starting from 4097...

1002h = Phase voltage L1-N so it should appear in 4098 register but L1-N voltage around 230v so value will displayed in 4099........

hope got the ides...

bye